Mining Park of La Unión Monument · La Unión, Campo de Cartagena, Murcia A complex for the rehabilitation of industrial heritage that recovers eight former 19th-century mining sites over 50,000 square metres of the Sierra Minera, toured by means of a tourist mining train. It was inaugurated on 9 July 2010 and preserves facilities such as the tailings pond, where waste from the washing plants was accumulated, the ball mill where the ore was crushed, the roasting furnaces, where the ore was calcined with wood or coal, and the powder magazines where explosives were stored. Also notable is the chimney-coil of the Trinidad Rentero Lead Smelter, zigzagging brick galleries built into the hillside, through which the smoke cooled while the lead condensed on their walls, from where it was later recovered. Photo: DMzlC (CC BY-SA 4.0) What to see and do in La Unión